Grand Designs - Riba House of the Year, episode four: a London 'tin house' and a 'Portakabin' home that was objected to by 30 neighbours are up for top prize - and the winner is announced

In the fourth and final episode of Grand Designs: House of the Year, the focus is on homes that make the most of challenging building plots - and the winner of the prize is announced.

Grand Designs presenter Kevin McCloud says the remaining houses on the long list of Royal Institute of British Architects House of the Year contest "have risen out of the ground to make the very best of the site they stand on".

1. ASIAN ZEN MEETS ENGLISH COUNTRY GARDEN
The Cheeran House, Reading, Berkshire

The most beautiful setting of the homes on this week's long list selection belongs to this modernist flint and cedar-clad house set in a walled meadow garden.

Architect John Pardey created the house for hospital consultants Binith and Cian and their growing family.

He combined Binith's south Indian heritage and Cian's Malaysian-Chinese and created a formal courtyard surrounded by four walls that sits next to beautiful and wilder walled garden.

Binith says he most delighted with the house that serves as a family home and a minimal masterpiece because it has so much hidden storage.

A wall hides a folding writing desk, the staircase conceals storage for the family's suitcases and there are even cupboards with step-shaped doors on the way up.

The judges loved the way house virtuously straddles two worlds - Asian courtyard, classic English walled garden and despite the house's location, Kevin concludes: "One thing it is not is the Home Counties."

2. HARD-FOUGHT FAMILY HOME
Private House 1109, Cheadle Hulme, Cheshire

Pete and Sally faced not only opposition from 30 neighbours over plans for their new home, but also Pete's parents.

Faced with a tight budget, Michael and Jackie allowed the couple to build on what had been an allotment garden area, but Michael admits that even now it's not to his taste.

Sally says: "We thought we'd have to build a traditional house but the planners said that it had to be contemporary, it had to have architectural merit."

Although architect David Lambert incorporated greenery and timber into the design, Sally admits to Pete: "Your dad was horrified, said it looks like a factory." Somebody else likened it to three Portakabins stacked on top of each other.

Despite the objections, the house was eventually built and the Riba judges praised Lambert for creating a beautiful home on such a tightly constrained site, a limited budget and with the proximity of so many neighbours.

Kevin says that the house is a wonderful example of "crafted architecture that carefully infills suburbia and brings together the generations".

3. RED SHEDS
Tin House, west London

Architect Henning Stummel and his wife Alice turned a contaminated breakers' yard into a horseshoe-shaped collection of steel red oxide-coated rooms that form their family home.

They spent £50,000 of their £700,000 budget decontaminating the earth and in its place build an amazing timber-framed house clad in Swedish steel - that came in rolls and was cut to length with shears.

The house is reached via a vast arch that looks like it should belong in a Victorian railway station and Kevin calls it "a magic, personal wonderland".

He adds: "The judges loved the sculptural quality of the project and playfulness of the design which transformed a piece of London wasteland into an architectural jewel."

4. A TRICK OF THE LIGHT
Edge Hill, Newcastle-upon-Tyne

A planning committee's insistence on a pitched roof in a suburb of Newcastle turned this house into the gem it is today.

Architect Colin Harris not only realised he could gain more space under such a roof, but it allowed him to create a double-height hallway that brings light flooding through the entire house.

Kevin calls the hallway alone "a staggering piece of theatre, a light sculpture".

Owner Rob says of realising his dream home: "If you can you want to get a little bit of where you want to be all the time - which is on holiday."

Grand Designs: House of the Year is on Channel 4 on Thursdays at 9pm

Of the four houses detailed here, one was placed on the Riba House of the Year shortlist and the winner of the entire contest will be announced at the end of the show...